Not sure if it was a bubble, or just the markets overheating...
I'm sure it isn't by now, and yes - the market did do a nice exponential-like blowoff before settling down again. This actually happens from time to time in commodities due to supply problems (although limits on daily trading offset this effect partially).
Can't wait to see what happens next - we've had some good progress in the last few weeks, steady fill and grind, not the spike/collapse we saw last summer.